Colorado Gov. John Hickenlooper, a Democrat, again joined with Republican Gov. John Kasich of Ohio in a bipartisan showing of opposition to the U.S. Senate health care bill.

Hickenlooper and Kasich brought together a group of 10 governors in sending a letter to Senate leadership to voice their concerns with the legislation.

The governors call upon the Senate “to reject efforts to amend the bill into a ‘skinny repeal,'” which the elected officials fear would result in fewer Americans having access to coverage.

The letter is addressed to Senate Majority Leader Mitch McConnell, a Republican from Kentucky, and Senate Minority Leader Chuck Schumer, a Democrat from New York.

“We urge you to set aside this flawed bill and work with governors, both Democrats and Republicans, on solutions that will make health care more available and affordable for every American. True, lasting reforms can only be achieved in an open, bipartisan fashion,” the letter states.

In addition to Hickenlooper and Kasich, governors from Louisiana, Montana, Virginia, Nevada, Massachusetts, Maryland, Pennsylvania and Vermont signed the letter. Hickenlooper and Kasich have been routinely speaking out against congressional health reform efforts in recent weeks.

The Senate this week narrowly approved a procedural motion to begin debate on legislation aimed at repealing the Affordable Care Act. The question is what Republicans come up with to replace so-called “Obamacare.” The Senate has settled in for a lengthy debate on various proposals.

The focus is on a so-called “skinny bill,” which would rollback the Obama-era health care law on individual and employer mandates.

U.S. Sen. Cory Gardner, a Colorado Republican, voted this week to move ahead with debate, lending a crucial vote that contributed to the dramatic 51-50 victory for President Trump, in which Vice President Mike Pence cast the tie-breaking vote.

The 10 governors in their letter pointed to Sen. John McCain, R-Ariz., who returned from Arizona, where he is battling brain cancer, to cast a crucial vote on proceeding on the health care debate. McCain called for a “return to regular order” and working across the aisle.

“Congress should be working to make health insurance more affordable while stabilizing the health insurance market, but this bill and similar proposals won’t accomplish these goals,” the governors wrote to Senate leaders.

They hope to fix unstable insurance markets and control costs.

“The next best step is for senators and governors of both parties to come together to work to improve our health care system,” the governors wrote. “We stand ready to work with lawmakers in an open, bipartisan way to provide better insurance for all Americans.”